Exhaust duct



FIG. 1 is a top perspective view of an exhaust duct showing our new design;

FIG. 2 is a bottom perspective view thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a bottom plan view thereof;

FIG. 5 is a front elevational view thereof;

FIG. 6 is a rear elevational view thereof;

FIG. 7 is a right side elevational view thereof;

FIG. 8 is a left side elevational view thereof; and,

FIG. 9 is a cross-sectional view thereof. 

CLAIM The ornamental design for an exhaust duct, as shown and described. 